Goodwill and Intangibles - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Amortized intangible assets:
Gross carrying amount	$ 59,130	$ 42,930
Accumulated amortization	(17,595)	(11,662)
Net intangible assets, excluding goodwill	41,535	31,268
Unamortized intangible assets:
Gross carrying amount	9,960	9,960
Net intangible assets, excluding goodwill	9,960	9,960
Gross carrying amount	69,090	52,890
Accumulated amortization	(17,595)	(11,662)
Total amortized and unamortized assets, excluding goodwill	51,495	41,228
Trade name - Limbach
Unamortized intangible assets:
Gross carrying amount	9,960	9,960
Net intangible assets, excluding goodwill	9,960	9,960
Customer relationships
Amortized intangible assets:
Gross carrying amount	47,620	32,820
Accumulated amortization	(10,419)	(7,124)
Net intangible assets, excluding goodwill	37,201	25,696
Unamortized intangible assets:
Accumulated amortization	(10,419)	(7,124)
Backlog
Amortized intangible assets:
Gross carrying amount	5,960	5,560
Accumulated amortization	(5,118)	(3,310)
Net intangible assets, excluding goodwill	842	2,250
Unamortized intangible assets:
Accumulated amortization	(5,118)	(3,310)
Trade name, trademarks and intellectual property
Amortized intangible assets:
Gross carrying amount	5,550	4,550
Accumulated amortization	(2,058)	(1,228)
Net intangible assets, excluding goodwill	3,492	3,322
Unamortized intangible assets:
Accumulated amortization	$ (2,058)	$ (1,228)